Midterm 2 - Unit 4 Lecture 2 Flashcards
what is the Signal Detection Theory
The ability to differentiate between “information-bearing patterns” (stimulus/signals) and “random patterns” that distract from the information
a method of differentiating a person’s ability to discriminate the presence and absence of a stimulus
what does Signal Detection Theory explain
how changing the threshold will affect the ability to discern, often exposing how adapted the system is to the task, purpose or goal at which it is aimed
Perceptual sensitivity(strength of signal) is denoted by…
d’ (d prime)
what is the strict/conservative strategy in the Signal Detection Theory
minimizes false alarms but increases exposure to missed detections.
responds no more often than an ideal observer
what is the lax/liberal strategy in the Signal Detection Theory
a lower criterion for judging that a target is present
participant responds no less often than the ideal observer
Perceptual performance depends on..
Perceptual sensitivity of the performer
Expectancies about the performer and the rewards and penalties inherent in the situation
what does a high d prime mean in signal detection theory
Larger absolute values of d’ mean that a person is more sensitive to the difference between the Signal Present and Signal Absent distributions
what does a low d prime mean in signal detection theory
low d prime values means it is harder to tell the difference between signal present and signal absent
Change in d’ can be due to
Environmental conditions
e.g., Weather while driving
Individual differences
e.g., Experience (novice v. experienced)
what is beta (β ) in signal detection theory
β is the signal dection theory’s measure of response bias – how willing the observer is to say that the signal was presen
what are the 4 outcomes of signal detection theory
Hit = signal present, yes
Miss(type 2 error)= signal present, no
False alarm(type 1 error) = signal not present, yes
Correct rejection/negative= signal not present, no
